Sexual and reproductive traits of Hypania invalida (Polychaeta, Ampharetidae): a remarkable invasive species in Central European waterways

Abstract

1. The Ponto-Caspian polychaete Hypania invalida (Archiv fü r Naturgeschichte, 1860, 26, 109) is undergoing rapid range expansion in the Rhine and other central European waterways. We examined its reproductive traits in an attempt to account for its remarkable invasive success. 2. For the first time in this species, we found males, dioecy (gonochorism) and an exclusively sexual mode of reproduction; no indication for hermaphroditism or (unisexual) parthenogenesis, that could explain the rapid range expansion of H. invalida, was found.3. Our experimental evidence shows that H. invalida reproduces by males discharging their sperm into the water column while eggs are retained and fertilised in the female dwelling tubes. This mode of 'spermcast' reproduction is common in sessile benthic animals on wave-washed shores. 4. Fecundity of H. invalida ranged between 60 and 260 eggs per clutch and is increased by iteroparity (i.e. multiple cycles of oogenesis and egg-laying per specimen). Offspring are brooded for about 2 weeks before they leave the maternal dwelling tubes and disperse in the water column. 5. After connection to a supply of Rhine water, sediments in flumes were rapidly colonised up to a density of 12 000 ind. m )2 via the settlement of small larvae (<300 lm) from the water column; these reached sexual maturity approximately 12 weeks after settlement. 6. The reproductive traits of H. invalida give the species a high rate of dispersal. The capacity of its larvae to survive passage through pumps before settlement enables them to travel in the ballast water of ships. This might explain the upstream expansion of H. invalida in rivers. We conclude that further range expansion, and especially intercontinental transport of this polychaete, can only be prevented by improved ballast water treatment.

Developmental studies of the enigmatic wormCaobangia billetiGiard, 1893 (Annelida; Sabellidae), a symbiont of freshwater snails

“…At the same time, exceptions are present. For example, the freshwater serpulid, Marifugia cavatica Absolon & Hrabě, 1930, and the ampharetid, Hypania invalida (Grube, 1860), are broadcast-spawners (Rouse, 2004; Norf et al ., 2010).…”

The influence of hydrology and sediment grain-size on the spatial distribution of macroinvertebrate communities in two submerged dunes from the Danube Delta (Romania)

“…The oligochaetes, the polychaete H. invalida, the chironomids, and the amphipod C. curvispinum showed the highest densities in this microhabitat (Table 3). All these taxa are known to occur in fine-sized, organically rich substrates in rivers and streams (Norf et al, 2010, Van den Brick et al, 1993), hence their presence in large numbers in this microhabitat. The lower values recorded for Reynolds number and critical shear stress concur with the accumulation of fine, organically rich sediments in trough microhabitat of D2 (Fig.…”

“…Moreover, the turnover rates for the benthic assemblages were of approximately one year, associated with diminished taxonomic richness of the benthic community and dominated by ubiquitous, fast colonising, r-type strategist species (Fredette & French, 2004). The majority of macroinvertebrates inhabiting both dunes comprised ubiquitous, fast colonising, r-type strate-gist species (Norf et al, 2010, Van Riel & Van der Velde, 2006. By contrast, the snails A. lacustris and L. naticoides, as the mussel U. pictorum are slow dispersals and K-strategists (Kappes & Haase, 2012, Mouthon, 2007 and were present in low numbers in D2 (Table 3).…”

Alien freshwater polychaetesHypania invalida(Grube 1860) andLaonome calidaCapa 2007 in the Upper Odra River (Baltic Sea catchment area)

“…Although some of them have been recently introduced into various new areas, invasive polychaetes make up a very small proportion of the total number of species (Cinar, 2013). Hypania invalida is such an invasive species of the Ponto Caspian origin which, until now, has been the only polychaete inhabiting inland waters of Central Europe (Norf et al, 2010). Over the last 35 years, it spread widely and rapidly in Europe through the Volga, Dnieper, and Danube catchments (Woźniczka et al, 2011 and references therein).…”

“…H. invalida is known for its ability to spread upstream rivers. The larval stages travel with ballast waters of small vessels (Norf et al, 2010). On the other hand, the Odra has been intensively sampled in recent years by a number of Polish researchers without any record of H. invalida and L. calida between the river mouth and Zdzieszowice (Bącela, personal communication; Krodkiewska, unpublished results).…”